Two astronomers have set up a small telescope with a CCD video camera to see if they could capture the faint flash from a lunar impact. And they nailed one on their first night! It’s almost certainly an impact; they investigated other possible causes (a satellite flash, a meteor in the Earth’s atmosphere, a cosmic ray zapping their equipment) and were able to rule them out. It looks real to me.

There have been other meteoroid impacts seen in the past. In fact, there has been a rich history of flashes on the Moon, collectively called "Lunar Transient Phenomena". Some areas seem prone to them; the crater Aristarchus once had a red flash in it which some people thought might have been volcanic! But it was never confirmed.

Years ago, that got me thinking. I got interested in setting up a project to observe these flashes. If they are meteoroids, then you need to look at the dark part of the Moon. Your best bet would be a small ‘scope that could see the entire Moon at once, and a video camera that takes thousands of individual frames. It would have to automatically process them; take an image, take a second image, subtract them, and look for a place where the brightness has suddenly changed. You’d need a robotic telescope, but it wouldn’t even have to be a dark site, since the flashes are fairly bright…

In the end, it was a pretty big undertaking for one guy. I told a few folks about it and they agreed it would be interesting, but a pain to set up. Also, getting a grant to do it would be a big time sink, and I was busy at the time (I was just starting to write my book). So I never pursued it.

Figures.

Actually, this would be a relatively easy thing for an amateur to do now. A six-inch telescope would probably be enough, in fact. The flash seen in November was at 7th magnitude, which is not hard to spot with binoculars, so even a small ‘scope would do it. And, in fact, having more people doing this is important, vital even– it can help distinguish real lunar impacts from something local (like a satellite or airplane). If two different telescopes at widely different locations spot it, that makes the case pretty solid for an impact.

Comments (15)

What do they call that in ShowBiz: “A flash-in-the-pan” In the creation and cratering of the lunar surface ( before photography) how many holes in the Moon land came from the subject event. Do technological tools change anything? No. The pounding of our big moon’s surface shall go on&on&on&on&on….

Just out of curiosity, is there a reliable source chronicling lunar impacts over the last half a century or so? I’d be most curious to see if anyone’s developed a frequency curve based upon modern observations (and without getting into the oft-wooÂ² area of TLP).

When I was a teenager and the astronauts were making their first run around the moon, I was an observer at the Hidden Valley Observatory
outside Rapid City, South Dakota. I observed an LTP in Aristarchus during that flight and reported it via a group of amateur radio ops then called Astronet. I don’t recall it being red. All I remember was a sudden brightening which I reported. Another observer reported it that same night. Was it important? I think so. We need to keep an eye on our near neighbor. It’s much more active than we think it is. We’re just used to it.
It’s familiar and we think it’s boring because “we’ve been there, done that.”
Well??? one never knows what our moon has saved us from and continues to save us from that zipping around our neighborhood. Take another look at the moon some night when it’s just a sliver. Maybe you’ll see something, too.

A reliable source? Beats me. I know there are LTP sites out there, but I’m not sure how accurate they are. Understandably, though regretably, this topic attracts people who are less than critical in their thinking.

Add a spectrometer to the telescopes, and you’ve got a research project.

If one group of geeks get a hit on their first night, a bit of budget could tell us lots about meteoroids.

Numbers of strikes, compositions of bodies. Energy at impact (from impact chemistry). Flare/dust plume shape could give us an idea about orbits. Tie that back to composition, and we’ve got data on solar system formation.

BA, that allegedly-red flash in Aristarchus could perhaps have been an iron meteoroid hitting with enough speed to vapourise part of itself. Doesn’t ionised iron glow with an orange-red colour? Of course, as Charles Randles points out, you’d need a spectrometer pointing at it to be sure.

Gordon – you should call it an EFFT, then (even faster Fourier Transform).